import java.io.*;
import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        int n = sc.nextInt();
        int q = sc.nextInt();
        int[] values = new int[n + 1];
        long[] sums = new long[n + 1];
        long[] totals = new long[n + 1];
        for (int i = 1; i <= n; i++) {
            values[i] = sc.nextInt();
            sums[i] = sums[i - 1] + values[i];
            totals[i] = totals[i - 1] + sums[i];
        }
        StringBuilder sb = new StringBuilder();
        while (q-- > 0) {
            int x = sc.nextInt();
            if (totals[n] < x) {
                sb.append(-1).append("\n");
                continue;
            }
            int left = 0;
            int right = n;
            while (right - left > 1) {
                int m = (left + right) / 2;
                if (totals[m] >= x) {
                    right = m;
                } else {
                    left = m;
                }
            }
            x -= totals[left];
            long ans = (left + 1L) * left / 2;
            left = 0;
            right = n;
            while (right - left > 1) {
                int m = (left + right) / 2;
                if (sums[m] >= x) {
                    right = m;
                } else {
                    left = m;
                }
            }
            sb.append(ans + right).append("\n");
        }
        System.out.print(sb);
    }
    
    static class Path implements Comparable<Path> {
        int idx;
        int value;
        
        public Path(int idx, int value) {
            this.idx = idx;
            this.value = value;
        }
        
        public int compareTo(Path another) {
            return value - another.value;
        }
    }
}

class Scanner {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    StringTokenizer st = new StringTokenizer("");
    
    public Scanner() throws Exception {
        
    }
    
    public int nextInt() throws Exception {
        return Integer.parseInt(next());
    }
    
    public long nextLong() throws Exception {
        return Long.parseLong(next());
    }
    
    public double nextDouble() throws Exception {
        return Double.parseDouble(next());
    }
    
    public String next() throws Exception {
        while (!st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }
}